1. Field of the Invention
The present invention relates generally to a wireless communication device and method for selecting a multi-band, and more particularly to a wireless communication device and method for selecting a multi-band by selecting an operable frequency band in accordance with an externally received frequency, and performing a communication with an external device according to the selected frequency band.
2. Description of the Related Art
Recently, wireless communication devices capable of performing a wireless communication using different communication systems or different frequency bands have been developed. Such wireless communication devices perform wireless communication by selecting an operable frequency band with respect to the different communication systems or frequency bands.
Wireless communication systems are conventionally divided into a global system for a mobile communication (GSM), a digital cellular system (DCS), and a personal communication system (PCS). A GSM and a DCS are used in Europe, and a PCS is used in The United States. The allocated frequency band for the wireless communication using GMS is in the range of 880 MHz to 960 MHz, and the allocated frequency band for the wireless communication using DCS is in the range of 1,710 MHZ to 1,880 MHz. The allocated frequency band for the wireless communication using PCS is in the range of 1,850 MHz to 1,990 MHz.
In a wireless communication device in which a variable band selection is possible with respect to a plurality of frequency bands receives frequencies set for a cell corresponding to its location, and compares the received frequencies with frequencies within the frequency band selected among the frequency bands of GSM, DCS, and PCS in order to synchronize with the received frequencies. In this case, if there is a frequency that belongs to the selected frequency band among the received frequencies, the wireless communication device selects the frequency band as its operational frequency band.
Selection of an operational frequency band using the conventional wireless communication device can be classified into three methods. First is a single band selection method for selecting one frequency band among the frequency bands of GSM, DCS, and PCS, and using the selected frequency band for the wireless communication. Second is a dual band selection method for selecting only two frequency bands among the frequency bands of GSM, DCS, and PCS, and using the two selected frequency bands for the wireless communication. Last is a manual band selection method for selecting the frequency band among the frequency bands of GMS, DCS, and PCS by a user's manipulation, and using the selected frequency band for the wireless communication.
The method for selecting an operational frequency band using the conventional wireless communication device will be described herein below. In explanation, it is exemplified that the wireless communication device is of an American type.
The conventional single band selection method has an advantage in that because it uses only a frequency band allocated to PCS for its operational frequency band, the time required for searching for a proper cell and entering into a normal service in an initial power-on state or a no-service state is shortened. However, the conventional single band selection method has a disadvantage that in Europe where frequency bands different from the United States, the service using the wireless communication device as described above cannot be provided.
The conventional dual band selection method has an advantage that the service can be provided in the United States and also in Europe. However, the conventional dual band selection method has a disadvantage that if there are many frequencies included in the frequency band allocated to GSM among the received frequencies, a synchronization error is frequently produced, and the time for entering into a normal service is delayed.
Finally, the conventional manual band selection method has an advantage that because the frequency band is selected by the user to be suitable for the present channel state, the problems produced in the single band selection method and the dual band selection method can be somewhat solved. However, the conventional manual band selection method has the disadvantage in that if the wireless communication device is located on a boundary between an area where the United State type frequency band is used and an area where the European type frequency band is used, the user must frequently manipulate the frequency bands allocated to the areas for a smooth reception of the service. Also, when using the manual band selection method, the user must be well acquainted with a provided manual for the frequency band selection.